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Zheng Yejian 9d1ac4ead6 tracing: Fix cpu buffers unavailable due to 'record_disabled' missed
[ Upstream commit b71645d6af ]

Trace ring buffer can no longer record anything after executing
following commands at the shell prompt:

  # cd /sys/kernel/tracing
  # cat tracing_cpumask
  fff
  # echo 0 > tracing_cpumask
  # echo 1 > snapshot
  # echo fff > tracing_cpumask
  # echo 1 > tracing_on
  # echo "hello world" > trace_marker
  -bash: echo: write error: Bad file descriptor

The root cause is that:
  1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers
     in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask());
  2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped
     with 'tr->max_buffer.buffer', then the 'record_disabled' became 0
     (see update_max_tr());
  3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1;
Then array_buffer and max_buffer are both unavailable due to value of
'record_disabled' is not 0.

To fix it, enable or disable both array_buffer and max_buffer at the same
time in tracing_set_cpumask().

Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <vnagarnaik@google.com>
Cc: <shuah@kernel.org>
Fixes: 71babb2705 ("tracing: change CPU ring buffer state from tracing_cpumask")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-05 01:25:05 +08:00
arch MIPS: cpu-features: Use boot_cpu_type for CPU type based features 2023-09-05 01:25:04 +08:00
block block/partition: fix signedness issue for Amiga partitions 2023-08-20 15:24:51 +08:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2023-04-19 17:50:34 +08:00
crypto KEYS: asymmetric: Copy sig and digest in public_key_verify_signature() 2023-08-20 15:21:12 +08:00
Documentation x86/cpu: Rename srso_(.*)_alias to srso_alias_\1 2023-08-28 23:27:07 +08:00
drivers drm/amd/display: check TG is non-null before checking if enabled 2023-09-05 01:25:05 +08:00
fs jbd2: fix a race when checking checkpoint buffer busy 2023-09-05 01:25:04 +08:00
include jbd2: fix a race when checking checkpoint buffer busy 2023-09-05 01:25:04 +08:00
init x86/mm: Initialize text poking earlier 2023-08-20 16:01:29 +08:00
io_uring io_uring: correct check for O_TMPFILE 2023-08-20 16:01:40 +08:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2023-04-19 17:56:54 +08:00
kernel tracing: Fix cpu buffers unavailable due to 'record_disabled' missed 2023-09-05 01:25:05 +08:00
lib test_firmware: return ENOMEM instead of ENOSPC on failed memory allocation 2023-08-20 15:24:43 +08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/damon/ops-common: atomically test and clear young on ptes and pmds 2023-08-20 15:24:58 +08:00
net can: raw: fix lockdep issue in raw_release() 2023-09-05 01:25:05 +08:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-08-20 16:01:05 +08:00
scripts kbuild: Disable GCOV for *.mod.o 2023-08-20 15:24:38 +08:00
security security: keys: Modify mismatched function name 2023-08-20 16:01:12 +08:00
sound ALSA: pcm: Fix potential data race at PCM memory allocation helpers 2023-09-05 01:25:04 +08:00
tools objtool/x86: Fix SRSO mess 2023-09-05 01:25:02 +08:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2023-04-19 17:44:58 +08:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-20 16:01:23 +08:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-28 23:26:58 +08:00
Makefile Linux 5.15.128 2023-08-28 23:27:08 +08:00
README
stfsync.txt add file to track last rebase commit from stf 2023-08-21 00:12:49 +08:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.